Five Turkish soldiers have been killed and five others have been injured in northwestern Syria by artillery fire from the Syrian army, Turkey’s ministry of defense reports.
Shells reportedly hit a Turkish observation post at Taftanaz airbase in the opposition-held Idlib province, where a major offensive is underway by pro-government forces.
Turkish forces have retaliated in the area by bombing targets for the Syrian army.
Eight Turkish militants died in a similar attack a week ago.
Aided by Iran-backed militia and Russian airstrikes, Syrian forces have seized hundreds of towns and villages in Idlib since December.
According to the United Nations, nearly 700,000 people, the vast majority of them women and children, had been displaced by the war.
Turkey, which supports the Syrian opposition and fears a large influx of refugees, has provided the Syrian army to pull back 12 Turkish observation posts until the end of February. These were founded in Idlib under a deal with Russia and Iran in 2017.
It has also deployed hundreds of tanks and thousands of soldiers to improve the posts.
A statement from the Turkish Ministry of Defense reported that the five soldiers were killed on Monday in an “intense attack targeting our elements sent to the region in order to prevent clashes in Idlib, guarantee our border security and avoid migration and human tragedy.”
“The targets found in the area were immediately intensively attacked … The targets were destroyed and our martyrs ‘ blood was not left on the ground,” it said.
The Turkish media and the Syrian Human Rights Observatory (SOHR), a monitoring group based in the UK, stated that Syrian pro-government forces shelled Taftanaz airbase, about 13 km (8 miles) northeast of Idlib.
The SOHR said the attack killed six Turkish troops and four Syrian rebels.
Videos posted online reportedly showed helicopters transferring wounded soldiers across the border to Turkish hospitals.
Fahrettin Altun, the Turkish government spokesman, wrote on Twitter: “Turkey has retaliated against the attack to kill all enemy targets and avenge our fallen troops.”
“The war criminal, who directed the barbaric attack today, was threatening the whole international community, not just Turkey,” he said.
The Syrian army or government did not give any immediate comment.
Seven Turkish soldiers and a civilian contractor died last Monday when shells hit a position at Idlib, Turkey’s ministry of defense said. Turkish forces have “neutralized” 76 Syrian soldiers in response, it said.
Syrian state media said no casualties were reported. But the SOHR confirmed that Turkish fire killed at least 13 soldiers in the provinces of Idlib, Latakia, and Hama.
Two days later, Turkish President Recep Tayyip Erdogan threatened to push Syrian troops back to Idlib unless they withdraw behind observation posts from Turkey.
“We hope that in the month of February, the regime’s cycle of pulling back behind our observation posts is over,” he said. “If the regime does not pull back during this time, the job will have to be done by Turkey itself.”
The Syrian army vowed to continue its offensive and then recaptured the major town of Saraqeb, south of Taftanaz, straddling the junction of strategic highways M4 and M5.
The command of the Syrian armed forces has called the involvement of Turkish forces in Syria an “illegal and flagrant act of aggression.”
In the meantime, the UN Humanitarian Coordination Office cautioned that the number of civilians displaced by the crisis “spirals out of control.”
Spokesman David Swanson told AFP news agency that as of 1 December 689,000 of the three million people living in opposition-held Idlib had fled their homes.
It has exacerbated an already desperate humanitarian situation on the ground resulting from the displacement between April and August of more than 400,000 other people.
The UN Human Rights Office has since 1 January been checking the deaths of 180 civilians.